| 摘要 |
PROBLEM TO BE SOLVED: To obtain a reversal developing system image forming device capable of preventing fogging and soiling on the rear side of a transfer paper for a long period caused by the lowering of the charged potential on the photoreceptor surface due to the influence of a transfer voltage. SOLUTION: A non-contact type transfer roller 54 is controlled by a control part so that the polarity of the roller 54 when a paper passes through, that is, in operation of transferring an image to the transfer paper, may be completely opposite to the polarity of the roller 54 when the paper does not pass through, that is, in a period from the end of transferring the image to a certain transfer paper to the start of transferring the image to the following transfer paper. That is, in the same way as in the conventional practice, a positive voltage opposite to the charged polarity of the photoreceptor surface is applied on the non-contact type transfer roller 54 when the paper passes through, whereas, a negative voltage which is the same as the charged polarity of the photoreceptor surface is applied on the roller 54 when the paper does not pass through. Thus, the lowering of the potential at the non paper passing part on the surface of the photoreceptor drum 51 occurred at transferring to a small-sized transfer paper is recovered, then, the fogging and the soiling on the rear side of the transfer paper, etc., are prevented.
|
